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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 762 · 40 questions
TalentJR

The trick (Digits add to the 9 table): Add the digits you can see. Find the next number in the 9 table (9, 18, 27 …) above that total. The hidden digit is the difference. (Any number minus its digit sum is in the 9 table too.)

NameDateTime takenScore ___ / 40
  1. 1.?340 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.?093 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.2?48 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.857? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.Take 55 and take away the sum of its digits. What do you get?
  6. 6.Take 86 and take away the sum of its digits. What do you get?
  7. 7.Take 99 and take away the sum of its digits. What do you get?
  8. 8.Take 77 and take away the sum of its digits. What do you get?
  9. 9.Take 92 and take away the sum of its digits. What do you get?
  10. 10.?382 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.?497 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.Take 93 and take away the sum of its digits. What do you get?
  13. 13.?543 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.1?91 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.?285 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.87?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.422? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.Take 27 and take away the sum of its digits. What do you get?
  19. 19.Take 40 and take away the sum of its digits. What do you get?
  20. 20.?799 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.Take 18 and take away the sum of its digits. What do you get?
  22. 22.13?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.Take 33 and take away the sum of its digits. What do you get?
  24. 24.8?74 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.?01 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.Take 28 and take away the sum of its digits. What do you get?
  27. 27.Take 22 and take away the sum of its digits. What do you get?
  28. 28.885? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.?41 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.Take 23 and take away the sum of its digits. What do you get?
  31. 31.841? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.24?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 66 and take away the sum of its digits. What do you get?
  34. 34.?373 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.?707 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.Take 95 and take away the sum of its digits. What do you get?
  37. 37.?924 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.31?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.Take 41 and take away the sum of its digits. What do you get?
  40. 40.77?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

  1. 2
  2. 6
  3. 4
  4. 7
  5. 45
  6. 72
  7. 81
  8. 63
  9. 81
  10. 5
  11. 7
  12. 81
  13. 6
  14. 7
  15. 3
  16. 3
  17. 1
  18. 18
  19. 36
  20. 2
  21. 9
  22. 4
  23. 27
  24. 8
  25. 8
  26. 18
  27. 18
  28. 6
  29. 4
  30. 18
  31. 5
  32. 2
  33. 54
  34. 5
  35. 4
  36. 81
  37. 3
  38. 5
  39. 36
  40. 1

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